With the above-described control system for a working machine, each one of the plurality of control units controls a controlled object assigned thereto. Various kinds of information such as the input information inputted by the information inputting means provided in one control unit and information indicative of a control condition of the controlled object can be utilized for controlling in a further control unit. And, such information is transmitted as the control information from the one control unit to the further control unit via the data communication network. Further, when the control unit controls the controlled object assigned thereto, the unit uses the control management information. As one example of this control management information, the following data can be cited. That is, a control unit having an actuator as the controlled body capable of moving an operated object and a potentiometer type detecting sensor for detecting an operational position of the operated object uses fine adjustment data for adjusting individual difference in the detection values of the detecting sensor when the controlled body operated by the actuator is operated to a reference position. These fine adjustment data represent an example of the above data.
As a conventional example of such control system for a working machine, from JP-A-2005-059773 (Patent Document 1), there is known a system wherein each one of the plurality of control units includes a writable nonvolatile memory (EEPROM) for storing the control management information for use in each control unit.
The control management data such as the fine adjustment data described above are generally determined in advance and stored in the memory, prior to shipment of the working machine from the manufacturing factory. And, if a trouble develops in the detecting sensor or the actuator with use of the working machine, a maintenance operation is effected on this sensor or actuator. In this case too, determination of data and writing thereof into the memory are to be effected again. Therefore, in order to allow rewriting of the control management information and also to avoid inadvertent deletion of the stored information upon stop of power supply, the control management information is stored in the writable nonvolatile memory.
According to the above-described conventional technique, each one of the plurality of control units is equipped with the writable nonvolatile memory for storing the control management information, through which the control unit can control the assigned controlled object appropriately. However, since each one of the plurality of control units is equipped with the memory as described above, a large number of writable nonvolatile memories are required.    Patent Document 1: Japanese Patent Application “Kokai” No. 2005-059773 (JP-A-2005-059773).